During the past year we have continued islet isolation from human cadaver pancreata by various techniques. A mechanical tissue mincer has been developed which allows a pancreas to be processed rapidly. Culturing of minced pancreatic fragments has been shown to result in selective loss of exocrine tissue with purification of islet tissue. Neonatal pancreata of humans, rats and dogs have all been found to have high insulin/amylase ratios when compared to adult pancreata of each species. In the rat, the effect of collagenase digestion on neonatal pancreatic tissue insulin content has been determined, and quantitative studies have been performed to determine the amount of dispersed neonatal pancreas required to ameliorate diabetes when infused into the portal vein. Dipsersed neonatal dog pancreata have also been found to ameliorate diabetes when infused into the portal vein of a diabetic dog. Over the next year we will continue to improve techniques for purification of islet tissue from human cadaver pancreata. Further modifications and combinations of the collagenase digestion and tissue culture techniques will be attempted. Using experimental animals, islet tissue obtained by these various techniques will be transplanted into diabetic rats or dogs. The effect of warm and cold ischemia of various durations on neonatal rat and dog pancreata prior to transplantation to diabetic rats and dogs will be determined. We will continue to attmept cryopreservation of islet tissue. We will also compare various sites of transplantation in relation to amelioration of diabetes by known quantities of islet tissue. BIBLIOGRAPHIC REFERENCES: Matas, A.J., Sutherland, D.E.R., Steffes, M.W., and Najarian, J.S.: Islet Transplantation Using Neonatal Pancreas: Quantitative Studies. J. Surg. Res. (Accepted for Publication), 1976. Steffes, M.W., Sutherland, D.E.R., Mauer, S.M., Najarian, J.S., and Brown, D.M.: Plasma Insulin and Glucose Levels in Diabetic Rats Prior To and Following Islet Transplantation. J. Lab. and Clinical Med. 85:75-81, 1975.